Autoradiographic demonstration of adrenergic innervation to scale melanophores of a teleost fish, Oryzias latipes

Abstract

The possibility of adrenergic innervation to melanophores in scales of Oryzias latipes was investigated using 3H-norepinephrine ('H-NE) by light microscopic autoradiography. When isolated scales were incubated in 3H-NE, there was observed plexus of varicose fibers labeled with 3H-NE which intimately enclosed the stellate processes and cell bodies of melanophores. These labeled fibers could not be detected in cocaine-treated or denervated scales. Potassium ions caused a considerable reduction in the labeling of varicose fibers, which was accompanied with aggregation of melanosomes within melanophores. These findings suggest that the labeled fibers observed are compatible with adrenergic nerve fibers that control the melanosome movements within melanophores.

The Regulation of Motile Activity in Fish Chromatophores

“…By means of autoradiography using radiolabeled NE, Yamada et al (120) succeeded in visualizing the pattern of adrenergic innervation on melanophores of the medaka O. latipes clearly. They also demonstrated the pattern of innervation to erythrophores of the swordtail, X. helleri (121).…”

Control of organelle transport in melanophores: Regulation of CA2+ and cAMP levels

“…system [Finnin and Reed, 19731, since melanophores are innervated by nerve fibers that take up 3H-norepinephrine [Yamada et al, 1984;Miyata and Yamada, 19851 and subsequently release the labeled transmitter upon stimulation [Kumazawa and Fujii, 19841. Histochemical demonstration of the presence of catecholamines [Falck et al, 19621 in nerve fibers surrounding melanophores [Jacobowitz and Laties, 1968;Fernando, 19891 demonstrates monoaminergic innervation.…”

Responses of the melanophores of the medaka, Oryzias latipes, to adrenergic drugs: Evidence for involvement of alpha2 adrenergic receptors mediating melanin aggregation

“…Dermal melanophores of teleost fishes receive adrenergic innervation (Falck et al, 1969;Reed and Finnin, 1972;Yamada et al, 1984;also cf. Parker, 1948;Bagnara and Hadley, 1973;Fujii and Oshima, 1986) and both electric currents and potassium ions induce melanosome aggregation within the cells through stimulation of their nervous elements (Fuj ii, 1959;Fuj ii and Novales, 1969;Kinosita and Ueda, 1970;Iga, 1975).…”

“…Parker, 1948;Bagnara and Hadley , 1973;Fujii and Oshima, 1986). Previous physiological and histological investigations have suggested that both melanopho r es and leucophores of the medaka receive the same adrenergic lnnervation and that the neurotransmitter released is norepinephrine (Iwata et al, 1981;Iga, 1983;Yamada et al , 1984) . In physiological saline , melanophores usually maintain a fully melanosome-dispersed state and leucophores are in a fully leucosome-aggregated state.…”